1. Field of the Invention
The present invention relates to processes and devices for recording and reproducing multimedia contents by using dynamic metadata.
2. Present State of the Art
Numerous portable devices have existed for many years which are used for recording digital multimedia formats, such as audio, video and photographs. Besides these portable devices, an increasing number of cellular telephones have made their appearance which, in addition to providing the typical functions of a mobile telephone, also allow to record video clips or to take digital photographs in accordance with the latest digital compression standards.
Besides offering the typical capabilities of a cellular telephone, such devices are also characterized by a number of peculiarities that enrich their functionality, such as, for example, GPS localization systems, accelerometers, orientation sensors, brightness sensors, etc.
These devices currently allow taking digital photographs, which are then stored and sorted in files; in addition, these devices allow particular information, called “metadata”, which provides more information about a picture, to be automatically entered into the same files or into files associated therewith.
Some examples of metadata entered into particular fields of a file containing a digital photograph are the following: name of the manufacturer of the capturing device, capturing device model, photograph orientation, shooting date and time, exposition time, flash use, geographic coordinates, etc.
These metadata are fixed and non-dynamic. They are entered into particular areas of the file structure and are generally associated with digital photographs, but may also be used for multimedia contents of different kinds, such as audio and/or video, which vary over time.
For video-containing files, which are generally dynamic, these static metadata do not allow to optimally manage the visualization of the video on the display. In particular, if when shooting the video, for example, the video camera orientation changes, the metadatum associated with orientation is not modified. It follows that, during the subsequent reproduction of the video, the reproduction device may not realize that the shooting orientation has changed, with the consequence that the visualization of the video on the screen may not be automatically adapted. In general, this is particularly critical when the content is a part of a multimedia stream which can generally vary over time, and whose capture settings, such as shooting orientation direction, may also change, which is often the case especially with mobile and portable capturing devices.
Currently, several formats exist for defining metadata associated with images. The most common ones are EXIF (Exchangeable Image File Format) and IPTC (International Press Telecommunication Council).
EXIF is a metadata format which has been typically defined for images, whereas IPTC has defined a set of generic metadata formats for different types of files containing text, images or any multimedia content.
Some of these metadata are fixed and cannot be changed by the user, while other metadata, such as those specified by IPTC, are modifiable by the user. In both cases, however, they are static metadata, and therefore they are metadata which do not modify their own values coherently with the variable content of the multimedia file, which may change its own characteristics (e.g. shooting orientation) as shooting is taking place (in the typical case of a video content).
This is a problem because, in general, multimedia shooting may occur at different times, in different places and, as a consequence, in different environmental conditions; if these variations are not taken into account, the reproduction of the multimedia contents may not be optimal and may not be adapted to the environmental conditions which were present at shooting time.